/*
* $Id: mtd_blkdevs.c,v 1.27 2005/11/07 11:14:20 gleixner Exp $
*
* (C) 2003 David Woodhouse <dwmw2@infradead.org>
*
* Interface to Linux 2.5 block layer for MTD 'translation layers'.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/mtd/blktrans.h>
#include <linux/mtd/mtd.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/spinlock.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
static LIST_HEAD(blktrans_majors);
extern struct semaphore mtd_table_mutex;
extern struct mtd_info *mtd_table[];
struct mtd_blkcore_priv {
struct completion thread_dead;
int exiting;
wait_queue_head_t thread_wq;
struct request_queue *rq;
spinlock_t queue_lock;
};
static int do_blktrans_request(struct mtd_blktrans_ops *tr,
struct mtd_blktrans_dev *dev,
struct request *req)
{
unsigned long block, nsect;
char *buf;
block = req->sector;
nsect = req->current_nr_sectors;
buf = req->buffer;
if (!(req->flags & REQ_CMD))
return 0;
if (block + nsect > get_capacity(req->rq_disk))
return 0;
switch(rq_data_dir(req)) {
case READ:
for (; nsect > 0; nsect--, block++, buf += 512)
if (tr->readsect(dev, block, buf))
return 0;
return 1;
case WRITE:
if (!tr->writesect)
return 0;
for (; nsect > 0; nsect--, block++, buf += 512)
if (tr->writesect(dev, block, buf))
return 0;
return 1;
default:
printk(KERN_NOTICE "Unknown request %ld\n", rq_data_dir(req));
return 0;
}
}
static int mtd_blktrans_thread(void *arg)
{
struct mtd_blktrans_ops *tr = arg;
struct request_queue *rq = tr->blkcore_priv->rq;
/* we might get involved when memory gets low, so use PF_MEMALLOC */
current->flags |= PF_MEMALLOC | PF_NOFREEZE;
daemonize("%sd", tr->name);
/* daemonize() doesn't do this for us since some kernel threads
actually want to deal with signals. We can't just call
exit_sighand() since that'll cause an oops when we finally
do exit. */
spin_lock_irq(¤t->sighand->siglock);
sigfillset(¤t->blocked);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
spin_lock_irq(rq->queue_lock);
while (!tr->blkcore_priv->exiting) {
struct request *req;
struct mtd_blktrans_dev *dev;
int res = 0;
DECLARE_WAITQUEUE(wait, current);
req = elv_next_request(rq);
if (!req) {
add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(rq->queue_lock);
schedule();
remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
spin_lock_irq(rq->queue_lock);
continue;
}
dev = req->rq_disk->private_data;
tr = dev->tr;
spin_unlock_irq(rq->queue_lock);
down(&dev->sem);
res = do_blktrans_request(tr, dev, req);
up(&dev->sem);
spin_lock_irq(rq->queue_lock);
end_request(req, res);
}
spin_unlock_irq(rq->queue_lock);
complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
}
static void mtd_blktrans_request(struct request_queue *rq)
{
struct mtd_blktrans_ops *tr = rq->queuedata;
wake_up(&tr->blkcore_priv->thread_wq);
}
static int blktrans_open(struct inode *i, struct file *f)
{
struct mtd_blktrans_dev *dev;
struct mtd_blktrans_ops *tr;
int ret = -ENODEV;
dev = i->i_bdev->bd_disk->private_data;
tr = dev->tr;
if (!try_module_get(dev->mtd->owner))
goto out;
if (!try_module_get(tr->owner))
goto out_tr;
/* FIXME: Locking. A hot pluggable device can go away
(del_mtd_device can be called for it) without its module
being unloaded. */
dev->mtd->usecount++;
ret = 0;
if (tr->open && (ret = tr->open(dev))) {
dev->mtd->usecount--;
module_put(dev->mtd->owner);
out_tr:
module_put(tr->owner);
}
out:
return ret;
}
static int blktrans_release(struct inode *i, struct file *f)
{
struct mtd_blktrans_dev *dev;
struct mtd_blktrans_ops *tr;
int ret = 0;
dev = i->i_bdev->bd_disk->private_data;
tr = dev->tr;
if (tr->release)
ret = tr->release(dev);
if (!ret) {
dev->mtd->usecount--;
module_put(dev->mtd->owner);
module_put(tr->owner);
}
return ret;
}
static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
if (dev->tr->getgeo)
return dev->tr->getgeo(dev, geo);
return -ENOTTY;
}
static int blktrans_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
struct mtd_blktrans_ops *tr = dev->tr;
switch (cmd) {
case BLKFLSBUF:
if (tr->flush)
return tr->flush(dev);
/* The core code did the work, we had nothing to do. */
return 0;
default:
return -ENOTTY;
}
}
struct block_device_operations mtd_blktrans_ops = {
.owner = THIS_MODULE,
.open = blktrans_open,
.release = blktrans_release,
.ioctl = blktrans_ioctl,
.getgeo = blktrans_getgeo,
};
int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
{
struct mtd_blktrans_ops *tr = new->tr;
struct list_head *this;
int last_devnum = -1;
struct gendisk *gd;
if (!down_trylock(&mtd_table_mutex)) {
up(&mtd_table_mutex);
BUG();
}
list_for_each(this, &tr->devs) {
struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
if (new->devnum == -1) {
/* Use first free number */
if (d->devnum != last_devnum+1) {
/* Found a free devnum. Plug it in here */
new->devnum = last_devnum+1;
list_add_tail(&new->list, &d->list);
goto added;
}
} else if (d->devnum == new->devnum) {
/* Required number taken */
return -EBUSY;
} else if (d->devnum > new->devnum) {
/* Required number was free */
list_add_tail(&new->list, &d->list);
goto added;
}
last_devnum = d->devnum;
}
if (new->devnum == -1)
new->devnum = last_devnum+1;
if ((new->devnum << tr->part_bits) > 256) {
return -EBUSY;
}
init_MUTEX(&new->sem);
list_add_tail(&new->list, &tr->devs);
added:
if (!tr->writesect)
new->readonly = 1;
gd = alloc_disk(1 << tr->part_bits);
if (!gd) {
list_del(&new->list);
return -ENOMEM;
}
gd->major = tr->major;
gd->first_minor = (new->devnum) << tr->part_bits;
gd->fops = &mtd_blktrans_ops;
if (tr->part_bits)
if (new->devnum < 26)
snprintf(gd->disk_name, sizeof(gd->disk_name),
"%s%c", tr->name, 'a' + new->devnum);
else
snprintf(gd->disk_name, sizeof(gd->disk_name),
"%s%c%c", tr->name,
'a' - 1 + new->devnum / 26,
'a' + new->devnum % 26);
else
snprintf(gd->disk_name, sizeof(gd->disk_name),
"%s%d", tr->name, new->devnum);
/* 2.5 has capacity in units of 512 bytes while still
having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
set_capacity(gd, (new->size * new->blksize) >> 9);
gd->private_data = new;
new->blkcore_priv = gd;
gd->queue = tr->blkcore_priv->rq;
if (new->readonly)
set_disk_ro(gd, 1);
add_disk(gd);
return 0;
}
int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
{
if (!down_trylock(&mtd_table_mutex)) {
up(&mtd_table_mutex);
BUG();
}
list_del(&old->list);
del_gendisk(old->blkcore_priv);
put_disk(old->blkcore_priv);
return 0;
}
static void blktrans_notify_remove(struct mtd_info *mtd)
{
struct list_head *this, *this2, *next;
list_for_each(this, &blktrans_majors) {
struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
list_for_each_safe(this2, next, &tr->devs) {
struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
if (dev->mtd == mtd)
tr->remove_dev(dev);
}
}
}
static void blktrans_notify_add(struct mtd_info *mtd)
{
struct list_head *this;
if (mtd->type == MTD_ABSENT)
return;
list_for_each(this, &blktrans_majors) {
struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
tr->add_mtd(tr, mtd);
}
}
static struct mtd_notifier blktrans_notifier = {
.add = blktrans_notify_add,
.remove = blktrans_notify_remove,
};
int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
int ret, i;
/* Register the notifier if/when the first device type is
registered, to prevent the link/init ordering from fucking
us over. */
if (!blktrans_notifier.list.next)
register_mtd_user(&blktrans_notifier);
tr->blkcore_priv = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
if (!tr->blkcore_priv)
return -ENOMEM;
memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv));
down(&mtd_table_mutex);
ret = register_blkdev(tr->major, tr->name);
if (ret) {
printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
tr->name, tr->major, ret);
kfree(tr->blkcore_priv);
up(&mtd_table_mutex);
return ret;
}
spin_lock_init(&tr->blkcore_priv->queue_lock);
init_completion(&tr->blkcore_priv->thread_dead);
init_waitqueue_head(&tr->blkcore_priv->thread_wq);
tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
if (!tr->blkcore_priv->rq) {
unregister_blkdev(tr->major, tr->name);
kfree(tr->blkcore_priv);
up(&mtd_table_mutex);
return -ENOMEM;
}
tr->blkcore_priv->rq->queuedata = tr;
ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL);
if (ret < 0) {
blk_cleanup_queue(tr->blkcore_priv->rq);
unregister_blkdev(tr->major, tr->name);
kfree(tr->blkcore_priv);
up(&mtd_table_mutex);
return ret;
}
INIT_LIST_HEAD(&tr->devs);
list_add(&tr->list, &blktrans_majors);
for (i=0; i<MAX_MTD_DEVICES; i++) {
if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
tr->add_mtd(tr, mtd_table[i]);
}
up(&mtd_table_mutex);
return 0;
}
int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
struct list_head *this, *next;
down(&mtd_table_mutex);
/* Clean up the kernel thread */
tr->blkcore_priv->exiting = 1;
wake_up(&tr->blkcore_priv->thread_wq);
wait_for_completion(&tr->blkcore_priv->thread_dead);
/* Remove it from the list of active majors */
list_del(&tr->list);
list_for_each_safe(this, next, &tr->devs) {
struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
tr->remove_dev(dev);
}
blk_cleanup_queue(tr->blkcore_priv->rq);
unregister_blkdev(tr->major, tr->name);
up(&mtd_table_mutex);
kfree(tr->blkcore_priv);
BUG_ON(!list_empty(&tr->devs));
return 0;
}
static void __exit mtd_blktrans_exit(void)
{
/* No race here -- if someone's currently in register_mtd_blktrans
we're screwed anyway. */
if (blktrans_notifier.list.next)
unregister_mtd_user(&blktrans_notifier);
}
module_exit(mtd_blktrans_exit);
EXPORT_SYMBOL_GPL(register_mtd_blktrans);
EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");